Xylem Phenology of Fagus sylvatica in Rarau Mountains (Eastern Carpathians, Romania)

Abstract

The cambium activity and the tree ring formation of European beech (Fagus sylvatica L.) from the Rarău Mountains was monitored during 2009, 2010 and 2011 in a beech - coniferous stand, representative for Eastern Carpathian mixed forests. Wood microcores were collected weekly from five trees and prepared in order to describe the different phases of wood formation. Four phases of tree ring development were quantified, in number of cells and phase duration: cambial phase, cell enlargement, cell wall thickening and cell maturation. The onset of the cambial activity took place in the first week of May 2009, one week later in 2010 and in the last week of April 2011. The beech tree ring development period varies between 127 days in 2009 and 137 days in 2011.